Abstract: Based on the frequency deviation problem of primary control of virtual synchronous generators in isolated island microgrid, a distributed secondary frequency control strategy based on predetermined time system is proposed. This strategy improves the consistency of the predetermined system and adapts the virtual synchronous generator ontology algorithm, so that each inverter only relies on the communication of adjacent units, and the active power deficit of the system can be distributed according to capacity and frequency without difference control. At the same time, the system can further improve the speed of frequency recovery by setting the convergence time of consistency in advance, without considering the impact of initial capacity and protocol parameters, which is conducive to the plug and play of distributed power supply and improve the operation efficiency. Finally, the feasibility and effectiveness of the proposed control strategy are verified by simulation.